Iron near absorption edge X-ray spectroscopy at aqueous-membrane interfaces
Employing synchrotron X-ray scattering, we systematically determine the absorption near-edge spectra (XANES) of iron in its ferrous (Fe2+) and ferric (Fe3+) states both as ions in aqueous solutions and as they bind to form a single layer to anionic templates that consist of carboxyl or phosphate groups at aqueous/vapor interfaces. While the XANES of bulk iron ions show that the electronic state and coordination of iron complexes in the bulk are isotropic, the interfacial bound ions show a signature of a broken inversion-symmetry environment. The XANES of Fe2+ and Fe3+ in the bulk possess distinct profiles however, upon binding they practically exhibit similar patterns. This indicates that both bound ions settle into a stable electronic and coordination configuration with an effective fractional valence (for example, Fe[2+nu]+, 0 < nu < 1) at charged organic templates. Such two dimensional properties may render interfacial iron, abundant in living organisms, a more efficient and versatile catalytic behavior.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-07CH11358
- OSTI ID:
- 1157659
- Report Number(s):
- IS-J 8373; PPCPFQ
- Journal Information:
- Physical Chemistry Chemical Physics, Vol. 16, Issue 26; ISSN 1463-9076
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pressure effect on the electronic structure of iron in Mg,Fe Si, Al O{sub 3} perovskite : a combined synchrotron Mossbauer and x-ray emission spectroscopy study up to 100 GPa.
Amorphous iron-(hydr) oxide networks at liquid/vapor interfaces: In situ X-ray scattering and spectroscopy studies